Stent designs

ABSTRACT

A stent may be constructed comprising a plurality of interconnected circumferential bands each bands comprising a plurality of concave and/or convex M-shaped segments joined together by loops.

BACKGROUND OF INVENTION

[0001] The use of stents in bodily lumen is well known. A stent istypically delivered in an unexpanded state to a desired location in abodily lumen and then expanded. The stent may be expanded via the use ofmechanical device such as a balloon or the stent may be self-expanding.

[0002] Because a stent often must be delivered through tortuous anatomy,it is desirable for the stent to be flexible. It is also desirable forthe stent to exhibit high scaffolding strength in the expanded state. Ingeneral, however, as stent flexibility is increased, scaffoldingstrength is decreased and similarly, as scaffolding strength isincreased, flexibility is decreased.

[0003] There remains a need for a stent having a high degree offlexibility in the unexpanded state and high scaffolding strength in theexpanded state.

[0004] All US patents and applications and all other published documentsmentioned anywhere in this application are incorporated herein byreference in their entirety.

[0005] The invention in various of its embodiment is summarized below.Additional details of the invention and/or additional embodiments of theinvention may be found in the Detailed Description of the Inventionbelow.

SUMMARY OF INVENTION

[0006] In one embodiment, the invention is directed to a stentcomprising a plurality of interconnected circumferential bands with aflowpath therethrough. At least one of the bands includes at least onesubstantially M-shaped segment selected from the group consisting ofconvex M-shaped segments and concave M-shaped segments. In the case of aconvex M-shaped segment, the segment comprises a first convex outer leg,a second convex outer leg and a connector connecting the first convexouter leg and the second convex outer leg. In the case of a concaveM-shaped segment, the segment comprises a first concave outer leg, asecond concave outer leg and a connector connecting the first concaveouter leg and the second concave outer leg.

[0007] Desirably, the at least one band comprises a plurality ofM-shaped segments whether convex, concave or both. Where present,adjacent convex M-shaped segments may be interconnected via a loopextending therebetween. The loop may optionally comprise a concave firstportion and a concave second portion. Where present, adjacent concaveM-shaped segments may be interconnected via a loop extendingtherebetween. The loop may optionally comprise a convex first portionand a convex second portion. Where convex M-shaped segments are presentin multiple bands, they may optionally be inverted relative to oneanother in adjacent bands. Similarly, where concave M-shaped segmentsare present in multiple bands, they may optionally be inverted relativeto one another in adjacent bands.

[0008] In another embodiment, the invention is directed to a stentcomprising a plurality of connected bands. At least one of the bandscomprises a repeating pattern of three or more substantially parallelinterconnected segments with a first curvature and three or moresubstantially parallel interconnected segments with a second curvature.One of the segments with the first curvature is connected to one of thesegments with the second curvature. Desirably, the first curvature isopposite to the second curvature. Also desirably, the stent comprises aplurality of the bands with each band comprising a repeating pattern ofthree or more substantially parallel interconnected segments with afirst curvature and three or more substantially parallel interconnectedsegments with a second curvature, one of the segments of the firstcurvature connected to one of the segments with the second curvature.

[0009] In another embodiment, the invention is directed to a stentcomprising a plurality of interconnected circumferential bands where atleast one of the bands has a proximal end and a distal end and one ofthe proximal and distal ends comprises at least one first loop and atleast one second loop. The first loop includes a portion which isdisposed substantially circumferentially and the second loop includes aportion which is substantially arrow shaped. Desirably, at least one ofthe bands comprises a plurality of first and second loops alternatingwith one another. Also desirably, the stent comprises a plurality ofsuch bands. Adjacent bands may be connected one to the other to formcombined bands with openings therein.

[0010] The invention is also directed to a stent comprising at least onefirst cell having a first end and a second end. The first end terminatesin a circumferential component and the second end terminates in anarrow-shaped component opposite the first end. The stent may comprise aplurality of such interconnected first cells. Desirably, the first cellsare interconnected circumferentially about the stent and/orlongitudinally along the length of the stent.

[0011] In another embodiment, the invention is directed to a stentcomprising a plurality of serpentine bands extending in a longitudinaldirection, including a first serpentine band and a second serpentineband. The first and second serpentine bands are connected by at leastone loop member and desirably a plurality of loop members extending in adirection non-parallel to the longitudinal axis of the stent. All orsome of the longitudinally adjacent first loop members may open towardthe proximal end of the stent. Optionally, longitudinally adjacent firstloop members may be oppositely oriented about the longitudinal axis ofthe stent. The stent may comprise additional serpentine bands extendingin a longitudinal direction and connected to adjacent serpentine bandsvia additional first loop members.

[0012] In another embodiment, the invention is directed to a stentcomprising at least one first cell comprising a first generallylongitudinal sidewall having at least one bend therein, a secondgenerally longitudinal sidewall having at least one bend therein,wherein the first generally longitudinal sidewall is substantiallyparallel to the second generally longitudinal sidewall, a proximal wallhaving at least one loop therein, the loop oriented non-parallel to thelongitudinal axis of the stent and a distal wall having at least oneloop therein, the loop oriented non-parallel to the longitudinal axis ofthe stent. Desirably, the stent comprises a plurality of such cellsarranged longitudinally and/or circumferentially about the stent. All ofthe loops in the proximal walls of the cells and all of the loops in thedistal walls of the cells may be substantially parallel to one anotheror may be non-parallel to one another.

[0013] In another embodiment, the invention is directed to a stentcomprising a plurality of bands, where each band comprises a pluralityof distally directed loops and a plurality of proximally directed loops.Each distally directed loop has an open end and a closed end and eachproximally directed loop has an open end and a closed end. Theproximally directed loops and the distally directed loops arenonparallel to the longitudinal axis of the stent and alternate aroundthe band. Optionally, the proximally directed loops and the distallydirected loops may be parallel to one another. Circumferentiallyadjacent proximally directed loops and distally directed loops areconnected to one another by first connectors which extend from the openend of the proximally directed loops to the open end of the distallydirected loops. The first connectors include a circumferentialcomponent. Bands which are adjacent one another are connected by one ormore second connectors extending therebetween. The second connectorsdesirably have at least one bend therein.

[0014] In another embodiment, the invention is directed to a stentdefined by a structure comprising a plurality of serpentine portions.Each serpentine portion has at least one peak and one trough. At leastsome of the serpentine portions advance discontinuously in a helicalpath about a longitudinal axis of the stent to form a discontinuoushelical band. The serpentine portions may also be arranged such that atleast some of the serpentine portions advance discontinuously in asubstantially longitudinal path about a longitudinal axis of the stentto form a discontinuousband extending substantially in a lengthwisedirection. Desirably, each of the serpentine portions forming thediscontinuous band consists of one peak and one trough where the peakand trough are disposed at a non-zero angle with respect to thelongitudinal axis of the stent. Also desirably, the serpentine portionsmay be arranged to form a plurality of discontinuous helical bands ordiscontinuous bands extending substantially in a lengthwise direction.All of the serpentine portions may be connected so as to form acontinuous path extending from one end of the stent to the other end ofthe stent.

[0015] In yet another embodiment, the invention is directed to a stentcomprising a meandering path of connected serpentine portions, eachserpentine portion comprising first and second loop portions which arearranged side-by-side and have a side in common. The first and secondloop portions each open in a non-longitudinal direction. Adjacentserpentine portions along the meandering path are connected by aconnector having a longitudinal component and a circumferentialcomponent. Furthermore, adjacent serpentine portions along themeandering path are displaced longitudinally and circumferentially fromone another. The serpentine portions may be arranged in at least onediscontinuous band extending in a substantially longitudinal directionor the discontinuous band may extend substantially helically about alongitudinal axis of the stent. Desirably, each serpentine portionconsists of a first loop and a second loop.

[0016] The invention is also directed to a stent comprising ameandering, substantially helical path of connected serpentine portionswhere each serpentine portion comprises first and second loop portionswhich are arranged side-by-side and have a side in common. The first andsecond loop portions each open in a non-longitudinal direction. Theserpentine portions may optionally be arranged in at least onediscontinuous band extending in a substantially longitudinal directionor in at least one discontinuous band extending substantially helicallyabout a longitudinal axis of the stent.

[0017] The invention is further directed to a stent comprising at leastone and desirably a plurality of omega building blocks. The omegabuilding block comprises a circumferentially oriented omega-shaped loop,a substantially proximally oriented first lobe extending from theproximal end of the omega-shaped loop and a substantially distallyoriented first lobe extending from the distal end of the omega-shapedloop. Where a plurality of omega building blocks are present, the omegabuilding blocks are desirably arranged in one or more bands extending ina lengthwise direction. Longitudinally adjacent omega building blocks inthe band extending in a lengthwise direction are connected by dual lobemembers. Each dual lobe member comprises a substantially proximallyoriented second lobe and a substantially distally oriented second lobeconnected to the substantially proximally oriented second lobe. Thesubstantially proximally oriented second lobe is at the proximal end ofthe dual lobe member and the substantially distally oriented second lobeis at the distal end of the dual lobe member. The substantially distallyoriented first lobe of an omega building block is arranged side by sideand has a side in common with the substantially proximally orientedsecond lobe of a dual lobe member and the substantially proximallyoriented first lobe of a longitudinally adjacent omega building block isarranged side by side and has a side in common with the substantiallydistally oriented second lobe of the dual lobe member. At least one anddesirably a plurality and more desirably all of the omega shaped loopsare connected circumferentially to circumferentially adjacent dual lobemembers between the substantially proximally oriented second lobe andthe substantially distally oriented second lobe.

BRIEF DESCRIPTION OF DRAWINGS

[0018]FIG. 1 illustrates a plan view of an expandable stent inaccordance with the present invention;

[0019]FIGS. 2a-f illustrates various connectors which may be used in theinventive stent disclosed herein;

[0020]FIG. 3 illustrates a plan view of an expandable stent inaccordance with the present invention;

[0021]FIG. 4 illustrates a plan view of another inventive stent;

[0022]FIG. 5 illustrates a plan view of another inventive stent;

[0023]FIG. 6 illustrates a plan view of another inventive stent;

[0024]FIG. 7 illustrates a plan view of another inventive stent;

[0025]FIG. 8 illustrates a plan view of another inventive stent;

[0026]FIG. 9 illustrates a plan view of another inventive stent; and

[0027]FIG. 10 illustrates a plan view of another inventive stent.

DETAILED DESCRIPTION

[0028] While this invention may be embodied in many different forms,there are described in detail herein specific preferred embodiments ofthe invention. This description is an exemplification of the principlesof the invention and is not intended to limit the invention to theparticular embodiments illustrated.

[0029] In one embodiment, the invention is directed to a stent such asthat shown generally at 100 in FIG. 1. Stent 100, shown as a flatpattern in FIG. 1, has a proximal end 102 and a distal end 104. Stent100 comprises a plurality of interconnected circumferential bands 106and 108 with a flowpath therethrough. Bands 106 are comprised ofconnected convex M-shaped segments 110 (shown highlighted) and bands 108are comprised of connected convex M-shaped segments 112 (shownhighlighted). Convex M-shaped segments 112 are inverted relative toconvex M-shaped segments 110. Bands 106 and 108 alternate over thelength of the stent and adjacent bands are connected to one another. Asshown in FIG. 1, an upper corner 114 of convex M-shaped segment 110 isconnected to an upper corner 116 of convex M-shaped segment 112 viaconnector 118. Adjacent bands may also be connected by other suitableconnectors 118 such as those shown in FIGS. 2a-f. The connectors mayextend exclusively in a longitudinal direction or may include acircumferential component as shown in FIG. 1 and as described incopending, commonly assigned U.S. application Ser. Nos. 08/511,076 and09/197,278. Adjacent bands may be connected by a plurality of connectorsas shown in FIG. 1 or by a single connector.

[0030] Convex M-shaped segment 110 comprises a first convex outer leg120, a second convex outer leg 122 and a connector connecting 124 firstconvex outer leg 120 and second convex outer leg 122. Inverted convexM-shaped segments 112 similarly comprise a first convex outer leg, asecond convex outer leg and a connector connecting the first convexouter leg and the second convex outer leg.

[0031] Adjacent convex M-shaped segments in a band are connected by aloop 126 comprising a first portion 128 and a second portion 130. Firstportion 128 is connected to a first concave leg 120 of a first convexM-shaped segment and second portion 130 is connected to a second concaveleg 122 of an adjacent convex M-shaped segment.

[0032] Desirably, as shown in FIG. 1, first portion 128 is substantiallyparallel to first concave leg 120 of the convex M-shaped segment andsecond portion 130 is substantially parallel to second concave leg 122of the adjacent convex M-shaped segment.

[0033] The invention also contemplates other shaped loops. Moreover, theinvention contemplates connecting adjacent M-shaped segments in a bandwith other types of connectors including any of those shown in FIGS.2a-f and those described in U.S. application Ser. No. 09/197,278. Suchconnectors may extend in a purely circumferential direction betweenpoints on adjacent M-shaped segments in a band, whether at the proximalor distal ends of the first and second legs of an M-shaped segment, thecenter or anywhere else along the first and second legs. The connectorsmay also include a longitudinal component.

[0034] The invention is also directed to a stent having at least oneconcave M-shaped segment with concave legs as shown at 111 in FIG. 1.Concave M-shaped segment 111 comprises first and second concave legsconnected by a loop portion.

[0035] The stent desirably comprises a plurality of concave M-shapedsegments 111 per band with circumferentially adjacent concave M-shapedsegments connected one to the other. Adjacent bands are alsointerconnected.

[0036] As shown in FIG. 1, the stent may be constructed and arranged tohave overlapping convex and concave M-shaped segments in each bands. Inthe embodiment shown in FIG. 1, the stent comprises alternating firstbands 106 having convex M-shaped segments 110 and second bands 108having convex M-shaped segments 112 which are inverted and similarly,concave M-shaped segments 111 and second bands 108 having concaveM-shaped segments 113. The inventive stents may also be formed of firstbands and second bands which do not alternate over the length of thestent. For example, a first portion of the stent may comprise bandshaving M-shaped segments of one orientation and a second portion of thestent may comprise bands having inverted M-shaped segments.

[0037] The invention also contemplates stents formed exclusively ofbands of M-shaped segments where the M-shaped segments are identicallyoriented.

[0038] The invention further contemplates stents having bands withdiffering numbers of convex and/or concave M-shaped segments. Forexample, a first band may consist of j M-shaped segments and a secondband may consist of k M-shaped segments where j is an integer greaterthan k. Moreover, the stent may comprise different bands havingdifferent amplitudes or differing strut widths and/or thicknesses. Thestent may be provided with a uniform diameter or may taper.

[0039] The invention is also directed to a stent, such as that showngenerally at 100 in FIG. 1 where at one of the bands comprises arepeating pattern of three or more substantially parallel interconnectedsegments 115 a-c with a first curvature and three or more substantiallyparallel interconnected segments 117 a-c with a second curvature. One ofthe segments 115 c with the first curvature is connected to one of thesegments 117 a with the second curvature. Desirably, the first curvatureis opposite to the second curvature. Also desirably, the stent comprisesa plurality of the bands with each band comprising a repeating patternof three or more substantially parallel interconnected segments with afirst curvature and three or more substantially parallel interconnectedsegments with a second curvature, one of the segments of the firstcurvature connected to one of the segments with the second curvature.

[0040] In another embodiment, the invention is directed to a stent suchas that shown generally at 200 in FIG. 3. Stent 200, shown as a flatpattern in FIG. 3, has a proximal end 202 and a distal end 204. Thestent comprises a plurality of interconnected bands 206 and 208. Bands206 and 208 are defined by-a plurality of alternating first loops 210(shown shaded) and second loops 212 (shown shaded). First loops 210include a circumferential portion 214 which is disposed substantiallycircumferentially and second loops 212 include a substantiallyarrow-shaped portion 216. Substantially arrow shaped is defined here tobe any shape resembling the head of an arrow. Bands 206 and 208 resembleone another but are oppositely oriented. That is, the arrow shaped loopsof bands 206 point in the proximal direction and the arrow shaped loopsof bands 208 point in the distal direction. Bands 206 and 208 are also180 degrees out of phase with one another.

[0041] Adjacent bands 206 and 208 are joined end-to-end to form acombined band 220. Combined bands 220 have a plurality of openings 222therein. As shown in FIG. 3, adjacent bands 206 and 208 abut oneanother. Adjacent bands 206 and 208 may also be connected using any ofthe connectors shown in FIGS. 2a-f. The connectors may extend entirelyin a longitudinal direction or may also include a circumferentialcomponent.

[0042] Adjacent combined bands are connected end-to-end along the lengthof the stent via connectors 218. Connectors 218 may also be replaced byany of the connectors shown in FIGS. 2a-f. The connectors may extendentirely in a longitudinal direction or may also include acircumferential component.

[0043] The invention is further directed to stents having a singlecombined band 220, the proximal or distal end of which comprises atleast one first loop 210 and at least one second loop 212. Desirably,the first loop 210 is an arrow shaped loop at one end and second loop212 comprises a substantially circumferential portion 214 at one end.More desirably, the stent comprises at least one combined band 220having a plurality of first loops 210 and second loops 212 and even moredesirably, the first and second loops alternate with one another.

[0044] The invention is also directed to a stent such as that showngenerally at 200 in FIG. 3, comprising at least one first cell 224(shown highlighted) having a first end 226 and a second end 228. Firstend 226 terminates in a circumferential component and second end 228terminates in an arrow-shaped component opposite first end 226.Desirably, the stent comprises a plurality of interconnected firstcells. The first cells may be interconnected circumferentially about thestent in bands and/or longitudinally along the length of the stent. Thefirst cells may be connected longitudinally and/or circumferentially asshown in FIG. 3 or using any of the connecting elements shown in FIGS.2a-f. The connectors may be exclusively longitudinal or circumferentialor may include longitudinal and circumferential components.

[0045] As shown in FIG. 3, the orientation of circumferentially adjacentfirst cells 224 alternate. The first end of every other first cell 224points in the proximal direction. The invention also contemplatesembodiments in which every first cell is identically oriented.

[0046] Where the stent comprises a plurality of bands 220 of first cells224, each band may consist of identically oriented first cells or firstcells with alternating orientations. The invention also contemplatesproviding one or more bands having first cells oriented exclusively inone direction and one or more bands having first cells orientedexclusively in the opposite direction. Such bands may alternate over thelength of the stent or may be provided in any other order along thelength of the stent.

[0047] The invention further contemplates stents having bands 220 withdiffering numbers of first cells 224. For example, a first band mayconsist of j first cells and a second band may consist of k first cellswhere j is an integer greater than k. Moreover, the stent may comprisedifferent bands having different amplitudes or longitudinal lengths ordiffering strut widths and/or thicknesses. The stent may be providedwith a uniform diameter or may taper.

[0048] In another embodiment, as shown in FIG. 4, the invention isdirected to a stent, shown generally at 300, having a proximal end 302and a distal end 304. Stent 300 comprises a plurality of serpentinebands 306 extending in a longitudinal direction, including a firstserpentine band 306 a and a second serpentine band 306 b. Firstserpentine band 306 a and second serpentine band 306 b are connected byat least one and desirably a plurality of loop members 308 a extendingin a direction non-parallel to the longitudinal axis of the stent.Longitudinally adjacent first loop members 308 a connecting firstserpentine band 306 a and second serpentine band 306 b open toward theproximal end of the stent. Longitudinally adjacent first loop members308 a may be non-parallel to one another, oppositely oriented about thelongitudinal axis of the stent as shown in FIG. 4 or may besubstantially parallel to one another, as shown in FIG. 5.

[0049] Stent 300 further comprises a third serpentine band 306 cextending in the longitudinal direction. Third band 306 c is adjacent tosecond band 306 b and connected thereto via a plurality of second loopmembers 308 b. Second loop members 308 b open toward the distal end ofthe stent. Longitudinally adjacent second loop members 308 b may benon-parallel to one another, oppositely oriented about the longitudinalaxis of the stent as shown in FIG. 4 or may be substantially parallel toone another, as shown in FIG. 5.

[0050] As shown in FIGS. 4 and 5, additional serpentine bands may bepresent as well, interconnected with loop members as described above.

[0051] The invention is also directed to a stent, such as that showngenerally at 300 in FIG. 4, comprising at least one first cell 320(shown highlighted) comprising a first generally longitudinal sidewall322 desirably having at least one bend therein and a second generallylongitudinal sidewall 324 having at least one bend therein. Firstgenerally longitudinal sidewall 322 is substantially parallel to secondgenerally longitudinal sidewall 324. Cell 320 further comprises aproximal wall 326 having at least one loop 328 therein and a distal wall330 having at least one loop 332 therein. Loops 328 and 332 are orientednon-parallel to the longitudinal axis of the stent.

[0052] Desirably, the stent comprises a plurality of first cellsarranged longitudinally in one or more rows along the length of thestent. The first cells are also seen to be arranged circumferentially inbands about the stent. In the embodiment shown in FIG. 4, for each cell,the loop in the proximal wall is non-parallel to the loop in the distalwall. In another embodiment of the invention, as shown in FIG. 5, all ofthe loops in the proximal walls of the cells and all of the loops in thedistal walls of the cells are substantially parallel to one another.

[0053] The invention is also directed to stents such as those shown inFIGS. 4 and 5 which are comprised of a plurality of bands 350 (shownhighlighted) where each band comprises a plurality of distally directedloops 308 b and a plurality of proximally directed loops 308 a. Eachdistally directed loop 308 b has an open end 352 and a closed end 354and each proximally directed loop 308 a has an open end 356 and a closedend 358. Desirably, proximally directed loops 308 a and distallydirected loops 308 b are parallel to one another and non-parallel to thelongitudinal axis of the stent. The proximally directed loops and thedistally directed loops alternate around the band and are connected toone another by first connectors 360 which extend from the open end 356of the proximally directed loops 308 a to the open end 352 of thedistally directed loops 308 b. First connectors 360 include acircumferential component. Bands which are adjacent one another areconnected by one or more second connectors 362 extending therebetween.Second connector 362 desirably has at least one bend therein and moredesirably, two bends.

[0054] As shown in FIGS. 4 and 5, the proximally directed loops inadjacent bands may be non-parallel with one another or parallel with oneanother.

[0055] The stents of FIGS. 4 and 5 may be provided in a number ofvariants. For example, the stent may be provided with a uniform diameteror may taper. Also, the width and/or thickness of the serpentine bandsand/or connectors may increase or decrease along a portion of the stent.

[0056] In another embodiment, the invention is directed to a stent suchas that shown generally at 400 in FIG. 6. Stent 400 has a proximal end402 and a distal end 404 and is defined by a structure comprising aplurality of serpentine portions 406 (shown highlighted). Eachserpentine portion 406 has at least one peak 408 and one trough 410,desirably disposed at a non-zero angle with respect to the longitudinalaxis 414 of the stent. Also desirably, each serpentine portion consistsof one peak and one trough although additional peaks and/or troughs maybe present.

[0057] Serpentine portions 406 may be provided in a variety of shapes.Desirably, however, the serpentine portions will be in the shape shownin FIG. 6, namely, in the shape of a first omega 418 joined side by sidewith a second omega 420, the second omega inverted relative to the firstomega and the first and second omegas having a side 422 in common. Theomegas are disposed at a non-zero angle relative to the longitudinalaxis of the stent.

[0058] At least some of the serpentine portions 406 advancediscontinuously along a helical path 412 a about a longitudinal axis 414of the stent to form a discontinuous helical band 416 a. Desirably,serpentine portions 406 are arranged to form a plurality ofdiscontinuous helical bands (e.g. 416 b, 416 c). The stent of FIG. 6 isprovided with three such discontinuous helical bands. Fewer oradditional discontinuous helical bands may be provided.

[0059] As shown in FIG. 6, all adjacent serpentine portions 406 within adiscontinuous helical band (416 a,b, or c) are separated from oneanother by gaps. Where the stent comprises a multiplicity discontinuoushelical bands, adjacent discontinuous helical bands (for example 416a-c) may optionally be connected to one another at one or more locations424.

[0060] Desirably, as shown in FIG. 6, serpentine portions 406 areconnected so as to form a continuous path extending from one end of thestent to the other end of the stent.

[0061] The embodiment of FIG. 6 may also be modified so thatdiscontinuous bands extending in a lengthwise direction are formed as isshown generally in FIG. 7. Stent 500 has a proximal end 502 and a distalend 504 and is defined by a structure comprising a plurality ofserpentine portions 506 (shown highlighted). Each serpentine portion 506has at least one peak 508 and one trough 510, desirably disposed at anon-zero angle with respect to the longitudinal axis 514 of the stent.Also desirably, each serpentine portion consists of one peak and onetrough although additional peaks and/or troughs may be present.

[0062] Serpentine portions 506 may be provided in a variety of shapes.Desirably, however, the serpentine portions will be in the shape shownin FIG. 7, namely, in the shape of a first omega 518 joined side by sidewith a second omega 520, the second omega inverted relative to the firstomega and the first and second omegas having a side 522 in common. Theomegas are disposed at a non-zero angle relative to the longitudinalaxis of the stent.

[0063] At least some of the serpentine portions 506 advancediscontinuously along a longitudinal path 512 about a longitudinal axis514 of the stent to form a discontinuous bands 516 a extending in alengthwise direction. Desirably, serpentine portions 506 are arranged toform a plurality of discontinuous bands extending in a lengthwisedirection (e.g. 516 b, 516 c). The stent of FIG. 7 is provided with atotal of four such discontinuous bands extending in a lengthwisedirection. Fewer or additional discontinuous bands extending in alengthwise direction may be provided.

[0064] As shown in FIG. 7, all adjacent serpentine portions 506 within adiscontinuous band (516 a,b, or c) extending in a lengthwise directionare separated from one another by gaps. Where the stent comprises amultiplicity discontinuous bands extending in a lengthwise direction,adjacent discontinuous bands extending in a lengthwise direction (forexample 516 a-c) may optionally be connected to one another at one ormore locations 524.

[0065] Desirably, as shown in FIG. 7, serpentine portions 506 areconnected so as to form a continuous path extending from one end of thestent to the other end of the stent.

[0066] The stents of FIGS. 6 and 7 and their variants discussed abovemay be provided with connectors to bridge the gap between adjacentserpentine portions within a given discontinuous helical (orlongitudinal) band. As shown in FIG. 7, connector 532 connectsserpentine portion 510 a to adjacent serpentine portion 510 b indiscontinuous band 516 a extending in a lengthwise direction. Some orall of the gaps within a discontinuous longitudinal (or helical band)may thus be bridged. Connectors 532 may be straight or curved and may beof the same thickness and/or width as the serpentine portions of thestent or may be of a smaller width and/or thinner.

[0067] One or more additional connectors may also be provided todirectly connect circumferentially adjacent serpentine portions. Anexample of such a connector is shown in FIG. 7. Connector 534 extendsbetween circumferentially adjacent serpentine portion 510 a and 510 c.Connectors 534 may be straight or curved and may be of the samethickness and/or width as the serpentine portions of the stent or may beof a smaller width and/or thinner.

[0068] In addition to the stent formation techniques disclosed below,the stents of FIGS. 6 and 7 and their variants may be made by winding awire in the desired pattern. The ends of the wire may optionally besecured to the stent as shown in FIGS. 6 and 7.

[0069] As shown in FIGS. 6 and 7, the invention is also directed to astent comprising a meandering path of connected serpentine portions 406(506). Each serpentine portion comprises a first loop portion 408 (508)and a second loop portion 410 (510) which are arranged side-by-side andhave a side in common. The first and second loop portions each open in anon-longitudinal direction. Adjacent serpentine portions along themeandering path are connected to one another end-to-end and aredisplaced longitudinally and circumferentially from one another alongthe meander path.

[0070] The serpentine portions may be arranged substantially helicallyabout a longitudinal axis of the stent as shown in FIG. 6, or in atleast one discontinuous band extending in a substantially longitudinaldirection as shown in FIG. 7.

[0071] The invention is also directed, as shown in FIGS. 6 and 7, to astent comprising a meandering, substantially helical path of connectedserpentine portions. Each serpentine portion comprises first and secondloop portions which are arranged side-by-side and have a side in common.The first and second loop portions each open in a non-longitudinaldirection. The serpentine portions may be arranged in at least onediscontinuous band extending substantially helically about alongitudinal axis of the stent or may be arranged in at least onediscontinuous band extending in a substantially longitudinal direction.

[0072] In addition to the variation discussed above, the stents of FIGS.6 and 7 and their variants may have a uniform diameter or may taper.Also, the-width and/or thickness of the serpentine portions may increaseor decrease along a portion of the stent.

[0073] The invention is also directed to a stent such as that showngenerally at 600 in FIG. 8. Stent 600 has a proximal end 602, a distalend 604 and a longitudinal axis 612. Stent 600 comprises an omegabuilding block 606 (shown highlighted). Omega building block 606comprises a circumferentially oriented omega-shaped loop 608 having aproximal end and a distal end, a substantially proximally oriented firstlobe 614 extending from the proximal end of omega-shaped loop 608 and asubstantially distally oriented first lobe 615 extending from the distalend of omega-shaped loop 608. Desirably, stent 600 comprises a pluralityof interconnected omega building blocks 606 arranged in a band 616extending in a lengthwise direction along the stent. Desirably,longitudinally adjacent omega building block members 606 in the band 616extending in a lengthwise direction are connected by dual lobe members620 (shown highlighted). Dual lobe member 620 comprises a substantiallyproximally oriented second lobe 622 and a substantially distallyoriented second lobe 624 connected to the substantially proximallyoriented second lobe 622. The substantially distally oriented first lobe615 of an omega building block 606 is arranged side by side and has aside in common with the substantially proximally oriented second lobe622 of a dual lobe member 620. The substantially proximally orientedfirst lobe 614 of a longitudinally adjacent omega building block 606 isarranged side by side and has a side in common with the substantiallydistally oriented second lobe 624 of the dual lobe member 620.

[0074] Desirably, as shown in FIG. 8, the stent comprises a plurality oflongitudinally adjacent dual lobe members. More desirably, the stentcomprises a plurality of bands extending in a lengthwise direction ofomega building blocks.

[0075] At least one of the omega shaped loops 606 is connectedcircumferentially to a circumferentially adjacent dual lobe member 620between the substantially proximally oriented second lobe and thesubstantially distally oriented second lobe as shown in FIG. 8. Any ofthe other connectors shown in FIGS. 2a-2 f may also be used. Moredesirably, each of the omega shaped loops is connected circumferentiallyto a circumferentially adjacent dual lobe member between thesubstantially proximally oriented second lobe and the substantiallydistally oriented second lobe.

[0076] The stent may be comprise a plurality of interconnected closedlongitudinal strips 630. Each closed longitudinal strip comprises twobands extending in a lengthwise direction of omega building blocks andtwo bands extending in a lengthwise direction of dual lobe members. Thestent shown in FIG. 8 comprises four such longitudinal strips. Theinventive stent may comprise fewer longitudinal strips or additionallongitudinal strips. Moreover, the longitudinal strips may be modifiedto have additional bands extending in a lengthwise direction of omegabuilding blocks and bands extending in a lengthwise direction of duallobe members.

[0077] In addition to the various techniques described below, theinventive stent of FIG. 8 and related embodiments may be made by windinga wire in the desired pattern.

[0078] Another embodiment of the inventive stents is shown generally at700 in FIG. 9. Stent 700, having a proximal end 702 and a distal end704, comprises a plurality of circumferential bands 705 (one of which isshown highlighted) and a plurality of bands extending in a lengthwisedirection 706 (one of which is shown highlighted) which significantlyoverlap the circumferential bands. The embodiment of FIG. 9 includesfour bands extending in a lengthwise direction. More generally, theinvention contemplates providing at least one and desirably a pluralityof bands extending in a lengthwise direction. Adjacent circumferentialbands include two types of connecting regions, a first region where aportion 709 (one of which is shown highlighted) of a band extending in alengthwise direction extends between adjacent circumferential bands anda second region where adjacent circumferential bands have a segment 711(one of which is shown highlighted) in common. The circumferential bandsare made of a plurality of hairpin curves 713 which alternate inorientation from a distal orientation 713 a to a proximal orientation713 b. Circumferentially adjacent hairpin curves are separated andjoined together by a curved portion 715 of the band extending in alengthwise direction. It is noted that the struts forming the bandsextending in a lengthwise direction are of a different width than thestruts forming the hairpin curves. As such, the circumferential bandsare formed in a repeating pattern of two wider struts followed by anarrower strut. The invention also is directed to embodiments in whichall of the struts are of the same width.

[0079] It is also noted that the stent of FIG. 9 comprises a pluralityof circumferential segments each comprising one or more R-shapedsegments 717 a (one of which is shown highlighted). Desirably, as shownin FIG. 9, the R-shaped segments are disposed at an oblique anglerelative to the longitudinal axis of the stent. Also desirably, eachband includes both R-shaped segments 717 a and inverted R-shapedsegments 717 b. In the embodiment of FIG. 9, adjacent bands areinterconnected by connectors. Also, adjacent R-shaped segments andinverted R-shaped segments in adjacent bands share a portion in common.In accordance with the invention, the inventive stents may have as fewas a single R-shaped segment. Desirably, however, one or more R-shapedsegments are provided in each band and more desirably, a plurality ofsuch segments are provided.

[0080] The invention is also directed to a stent, as shown in FIG. 9,comprising a plurality of circumferential bands 705 which areinterconnected by one or more connectors 709 extending between adjacentbands and which further are further connected by one or more segments711 shared in common between adjacent bands.

[0081] Yet another embodiment of the invention is shown at 800 in FIG.10. Stent 800, having a proximal end 802 and a distal end 804, comprisesa plurality of bands 806 extending in a lengthwise direction (one ofwhich is shown highlighted) of a first strut width interconnected by aplurality of circumferential connectors 805 (one of which is shownhighlighted). Bands 806 extending in a lengthwise direction includesubstantially oppositely directed loops 808 a,b. Circumferentialconnectors 805 desirably have a strut width which is narrower than thestrut width of bands 806 extending in a lengthwise direction althoughthe invention also contemplates the struts being of the same width orwider. Circumferential connectors 805 include loop 807 a oriented in thedistal direction, loop 807 b oriented in the proximal direction, and twoloops 809 a and 809 b oriented in opposite substantially circumferentialdirections. Proximally and distally oriented loops 807 a,b are disposedbetween adjacent bands 806 extending in a lengthwise direction.Substantially circumferentially oriented loops 809 a,b are each nestedin loops of adjacent bands 806 extending in a lengthwise direction.

[0082] More generally, the invention is directed to a stent having oneor more bands extending in a lengthwise direction and one or morecircumferential members. The circumferential members have two or moreloops at least one of which points substantially in the proximaldirection and at least one of which points substantially in the distaldirection. The circumferential members also include at least two loopswhich point in opposite, substantially circumferential directions.Desirably, a plurality of longitudinal members are present. Moredesirably, the longitudinal members also include loops which areoriented in substantially circumferential directions. Even moredesirably, at least some of the substantially circumferential loops ofthe circumferential members are nested within substantiallycircumferential loops of the longitudinal members. A stent in accordancewith this embodiment is shown in FIG. 10.

[0083] The invention is also directed to a stent comprising at least oneand desirably a plurality of longitudinal elements form a repeat patternof increasing width followed by a branching of the longitudinal elementwith the branch connecting the longitudinal element to an adjacentlongitudinal element. The longitudinal element decreases in width at thebranch and then increases in width again until another branch point isencountered. A stent in accordance with this embodiment is shown in FIG.10.

[0084] Any of the inventive stents disclosed above may be provided witha uniform diameter or may taper. Also, the width and/or thickness of thevarious portions of the inventive stents may increase or decrease alonga given portion of the stent.

[0085] Any of the inventive stents described above as comprising bandsmay include one or more bands of a first amplitude and one or more bandsof a second amplitude different from the first amplitude. Also, thosestents described above which are comprised of bands with repeatingstructural units may include one or more bands with a first number ofstructural units and one or more bands with a second number ofstructural units different from the first number. Examples of structuralunits include M-shaped segments 110 of FIG. 1 and cells 224 of FIG. 3.Bands with different amplitudes and/or numbers of repeating structuralunits may alternate with one another along the length of the stent.Bands with like amplitudes and/or numbers of repeating structural unitsmay also be grouped together.

[0086] The inventive stents may be manufactured using known stentmanufacturing techniques. Suitable methods for manufacturing theinventive stents include laser cutting, chemical etching, electroformingor stamping of a tube. The inventive stents may also be manufactured bylaser cutting, chemically etching, stamping or electroforming a flatsheet, rolling the sheet and welding the sheet, by electrode dischargemachining, or by molding the stent with the desired design. Theinventive stents may also be made by growing or extruding or winding astent with the inventive patterns.

[0087] Any suitable stent material may be used in the manufacture of theinventive stents. Examples of such materials include metals such asstainless steel, tantalum, elgiloy and shape memory metals such asnitinol and shape memory polymers. The inventive stents may also be madeof suitable polymeric materials.

[0088] The inventive stents may include suitable radiopaque coatings.For example, the stents may be coated with gold or sputtered withtantalum. The stents may also be made directly from a radiopaquematerial to obviate the need for a radiopaque coating or may be made ofa material having a radiopaque inner core.

[0089] The inventive stents may also be provided with variousbio-compatible coatings to enhance various properties of the stent. Forexample, the inventive stents may be provided with lubricious coatings.The inventive stents may also be provided with drug-containing coatingswhich release drugs over time. Suitable coatings include a sugar or moregenerally a carbohydrate and/or a gelatin to maintain the stent on aballoon during delivery of the stent to a desired bodily location. Othersuitable compounds for treating the stent include biodegradable polymersand polymers which are dissolvable in bodily fluids. Portions of theinterior and/or exterior of the stent may be coated or impregnated withthe compound. Subjecting the stent to such a treatment also may preventflaring of the ends of the stent during delivery of the stent.Mechanical retention devices may also be used to maintain the stent onthe balloon during delivery.

[0090] The inventive stents may be provided in mechanically expandableform, in self-expanding form or as a hybrid of the two. Mechanicallyexpandable stents, in accordance with the invention, may be expandedusing any suitable mechanical device including a balloon.

[0091] The inventive stents may be used for coronary arteries,peripheral arteries, arteries of the neck and intracranial arteries.More generally, the inventive stents may be used for any vessel of thehuman body including but not limited to arteries, veins, biliary ducts,urethras, fallopian tubes, bronchial tubes, the trachea and theesophagus.

[0092] Suitable stent delivery devices such as those disclosed in U.S.Pat. No. 6,123,712, U.S. Pat. No. 6,120,522 and U.S. Pat. No. 5,957,930may be used to deliver the inventive stents to the desired bodilylocation. The choice of delivery device will depend on whether aself-expanding or balloon expandable stent is used.

[0093] The inventive stents may also be used as the framework for agraft. Suitable coverings include PTFE and expanded PTFE or any of thematerials disclosed in U.S. Pat. No. 5,824,046 and U.S. Pat. No.5,755,770. More generally, any known graft material may be used.

[0094] In addition to the specific embodiments claimed below, theinvention is also directed to other embodiments having any otherpossible combination of the dependent features claimed below taken inconjunction with the independent claims from which they depend.

[0095] The above disclosure is intended to be illustrative and notexhaustive. The description will suggest many variations andalternatives to one of ordinary skill in this art. All thesealternatives and variations are intended to be included within the scopeof the attached claims. Those familiar with the art may recognize otherequivalents to the specific embodiments described herein whichequivalents are also intended to be encompassed by the claims attachedhereto.

1. A stent having a proximal end and a distal end, the stent comprisinga plurality of interconnected circumferential bands with a flowpaththerethrough, at least one of the bands including at least onesubstantially M-shaped segment selected from the group consisting ofconvex M-shaped segments and concave M-shaped segments.
 2. The stent ofclaim 1 wherein the at least one M-shaped segment is a convex M-shapedsegment.
 3. The stent of claim 2 wherein the convex M-shaped segmentcomprises a first convex outer leg, a second convex outer leg and aconnector connecting the first convex outer leg and the second convexouter leg.
 4. The stent of claim 2 wherein the at least one bandcomprises a plurality of convex M-shaped segments.
 5. The stent of claim2 comprising a first band having a plurality of interconnected convexM-shaped segments and a second band having a plurality of interconnectedconvex M-shaped segments.
 6. The stent of claim 5 wherein adjacentconvex M-shaped segments in the first band are interconnected via a loopextending therebetween.
 7. The stent of claim 6 wherein the loop isformed of a concave first portion and a concave second portion.
 8. Thestent of claim 5 wherein the convex M-shaped segments of the first bandare inverted relative to the convex M-shaped segments of the secondband.
 9. The stent of claim 8 wherein the convex M-shaped segments ofthe first bands at least partially abut and are connected.
 10. The stentof claim 1 wherein the at least one M-shaped segment is a concaveM-shaped segment.
 11. The stent of claim 10 wherein the concave M-shapedsegment comprises a first concave outer leg, a second concave outer legand a connector connecting the first concave outer leg and the secondconcave outer leg.
 12. The stent of claim 10 wherein the at least oneband comprises a plurality of concave M-shaped segments.
 13. The stentof claim 12 wherein the first portion is substantially parallel to thefirst concave leg of the first concave M-shaped segment and the secondportion is substantially parallel to the second concave leg of thesecond concave M-shaped segment.
 14. The stent of claim 10 comprising afirst band having a plurality of interconnected concave M-shapedsegments and a second band having a plurality of interconnected concaveM-shaped segments.
 15. The stent of claim 14 wherein adjacent concaveM-shaped segments in the first band are interconnected via a loopextending therebetween.
 16. The stent of claim 15 wherein the loop isformed of a convex first portion and a convex second portion.
 17. Thestent of claim 14 wherein the concave M-shaped segments of the firstband are inverted relative to the concave M-shaped segments of thesecond band.
 18. The stent of claim 17 wherein the concave M-shapedsegments of the first bands at least partially abut and are connected.19. The stent of claim 1 comprising a plurality of interconnected convexM-shaped segments and concave M-shaped segments.
 20. A stent comprisinga plurality of connected tubular bands, at least one of the tubularbands comprising a repeating pattern of three or more substantiallyparallel interconnected segments with a first curvature and three ormore substantially parallel interconnected segments with a secondcurvature, one of the segments with the first curvature connected to oneof the segments with the second curvature.
 21. The stent of claim 20wherein the first curvature is opposite the second curvature.
 22. Thestent of claim 20 wherein a plurality of the tubular bands each comprisea repeating pattern of three or more-substantially parallelinterconnected segments with a first curvature and three or moresubstantially parallel interconnected segments with a second curvature,one of the segments of the first curvature connected to one of thesegments with the second curvature.
 23. The stent of claim 22 whereinadjacent tubular bands are out of phase with one another.
 24. The stentof claim 22 wherein adjacent tubular bands are out of phase with oneanother by ninety degrees.